It all comes down to the user experience. It's a "lifestyle" difference, both functional and cosmetic. Honda vs. Hyundai, Lexus vs. Cadillac, Ferrari vs. Corvette. Macs are predominant in the creative industries: print media, tv, advertising, education, graphic design, web design, architecture, photography, etc. I believe this is because of the style and elegance of both the hardware and software. They look cool as well as work cool.
The Safari web browser is brilliant and stable. The DAs (formerly Desk Accesories) are now in a completely separate environment called Dashboard, which you can access via hot corners or a keystroke. Simple, elegant, efficient. There are hundreds of widgets that you can plug in and access in Dashboard, from sports scores to current weather to public radio and podcasts, all available instantly, without opening a browser or other app. The Spotlight search feature is powerful and simple to use. Expose is another cool feature. With the touch of a button, or a hot corner, you can do 3 different things: make all open windows and apps slide off the screen so you have instant access to the desktop. Hit the button again, and the windows re-appear. Or you can tile every open window and see whats in each simultaneously. The third opens all application-specific windows only. In practice, it's works nicely. If you're looking for something in another window, it only takes a second to tile all your open windows, find the window you want, and bring it to the front. Making all the windows disappear is great for managing files on your desktop, such as when you download things to it, save files to desktop, access a file/folder on the desktop, etc.
Both systems do everday legwork about equally, until you get to the extreme high-end, where the Macs do better (quicker) at things like image manipulation, digital photo file processing, and video/audio production. Icons and on-screen elements are clearer, smoother and more colorful on Macs, with less jaggies. Networking is very simple. If you know Unix, you can access the command line and go from there. It is extremely easy to uninstall stuff, whereas with Windows its a fucking nightmare.
You need head over to an Apple store or CompUSA and play around on one for a little while. Make a list of the things you want to play around with before you go. As far as gaming, I wouldn't go near a Mac for gaming. Games (and hardware) are DEVELOPED and OPTIMIZED for PCs, they are PORTED over to Macs. You probably know all this. Overall, Macs are cooler and funner to use than PCs.
Some busy Mac forums:
SpyMac Forums
MacNN Forums
Mac OSX Forums
iLounge (Music, podcasts, ipods)
MacOSX Hints